Recovery of so used in oil refining



June 13, 1933. s. CATTANEO RECOVERY OF $02 USED IN OIL REFINING Filed April 20, 1930 2 Sheets-Sheet 1 June 13, 1933. G. CATTANEO 1,913,658

RECOVERY OF $0 USED IN OIL REFINING Filed April 20, 1930 2 Sheets-Sheet 2 Eat/9.5.

Bis (Ittornegs Patented June 13, 1933 UNITED STATES PATENT OFFICE GIUBEPPE OAT'IAIIU, 01'

MVIBYOISQUSEDINOHIG Application fled April 90, 1982, Serial Io. 600,501, and in Germany Kay 3, 1.81.

5 be recovered in a sufliciently pure state for further use.

In practice, the liquid-SO, utilized in the treatment of petroleum fractions in a refining plant is recovered and reused, so that a continuous, cyclical operation is efiected and hence it is necessary that this recovered S be obtained in a substantially pure form so as not to interfere with the operation of the c cle.

The deleanu system consists, in brief, in dissolving the unsaturated and aromatic constituents of h drocarbon fractions by means of liquid-S A raflinate is secured which comprises substantially all of the saturated constituents, together with a relatively small quantity of liquid-SO (about 12 to 15 per cent), and an extract which comprises the unsaturated and aromatic constituents dissolved in a relatively large amount of liquid-S0,.

The raifinate and extract, respectivel are then freed of S0 by multi-stage distil ation or evaporation. The first stage in each case is usually operated at a pressure (45 to 7 pounds per square inch) suflicient to permit of the direct condensation of the evolved SO, vapors at cooling water temperature. The second sta is operated at atmospheric pressure and t e last stage under vacuum, the evolved SO vapors bein compresed to condenser-pressure for con ensation at cooling water temperature. The liquid-S0 so recovered is returned to the treatment cycle and thus utilized over and over again.

The practice has been to urify the S0, of water and hydrocarbons, w ich ass off with it from the evaporators, by su jecting the S0 vapors from the atmospheric-pressure and vacuum stages to cooling, for removal of hydrocarbons, and then to dving for removal of water. Under prevai ing practice, the S0 vapors from the condenser-pressure evatporators are directly condensed and reuse This procedure has the advantage that the ap aratus for separating out the hydro car as and water from e S0, is 0 rated at a low pressure insuring safety, t the disadvantage is that only a comparatively small part of the circulatin S0, is purl- N fied, since it has been tonn that the SO, vapors coming from the condenserressure evaporators contain a comparative y large ercentage of water and li ht oil and these 0, vapors are not purifi 00 In order to render the dryi and purification of the SO, vapors more e ective, and at the same time continue the use of the drying and cleaning devices only in the low pressure parts of the system, it is necessary to prevent 06 the wategtind light oils from the condenserpressure ges om assin with S0, va ors to the SO, condensgr. g P

The present invention solves this problem by contacting the S0 vapors derived from 10 the railinate and extract condenser-pressure evaporators with part of the uneva orated, cool, raflinate and extract, respective y, from the mixer. The contacting is effected in a suitable contact apparatus, such as a scrub- 15 her, in which the SO, vapors are assed countercurnently to the contacting iquid. The contact li uid, to ether with the oil and water remove from 5w SO vapors, is then introduced into the roper evaporating sys- 8'0 tem, either directly into the condenser-pressure evaporator or into the still unheated input liquid to this stage. As there is a constant stream of rafiinate or extract, as the case may be, flowing from the first stage evaporator to the succeeding stages, the water and light oil concentration in the first stage will not build up sufiiciently to interfere with its operation.

In the accompanying drawings, wherein several embodiments of the invention are shown for purposes of illustration, and in which like numerals designate corresponding P Fig. 1 is a flow sheet showing one embodiment of the invention in connection with a complete raflinate or extract evaporation system for recovery of S0,;

Fig. 2 is an enlarged vertical diagrammatic 1 representation of the contact device and first stage evaporator shown in ig 1;

Fig. 3 shows a second form of first stage evaporator and contact means; and

Fig. 4 shows a third form of the same.

Fig. 5 is a flow sheet showing the invention in connection with a complete rallinate and extract evaporation system for recovery of water-free S0 In the first embodiment of the invention selected for illustration and shown in Figs. 1 and 2 of the drawings, referring to Fig. l,

the rafiinate or extract solution from themixer (not shown) enters the evaporating system through line 1. At junction 2 the line is divided. line 3, controlled by valve 4 leads to the heating device 9 of condenser-pressure first stage evaporator 10, while line 5, controlled by valve 6, leads to contact device 7. Line 12 leads the SO, vapors from dome 11 of evaporator 10 to the contact device 7, and Sl) outlet line 13 which leads from the top of the contact device. Line 8 connects the bot-tom of the contact device to line 3.

The quantity of raflinate or extract, as the case may be, necessary for the contact device is controlled by the two regulating valves 4 and 6 and is diverted from line 1 into line 5 leading to the contact device. The undivcrted raffinate or extract flows through line 3 and is heated in heating device 9 before passing into evaporator 10. Here a portion of the S0 contained in the raflinate or extract is freed and rises as a vapor into dome 11, together with a certain amount of water and light oil vapors.

Referring now particularly to Fig. 2, the mixed vapors pass by line 12 into the bottom of contact device 7, which is shown in the form of a scrubber, and are directed upwardly by inlet 38. The scrubbing liquid, entering the top of scrubber 7 by line 5, is directed downwardly as a spray by means of sprinkler 28, and passes countercurrently to the ascending S0 vapors from the evaporator. Filling material 27, disposed between the sprinkler 28 and vapor inlet 38, serves to effect a more intimate and complete contacting between the descending scrubbing liquid and the ascending S0 vapors.

The action of the scrubbing liquid is to remove the water and oil vapors from the S0 vapors, so that a substantially pure S0 gas reaches the top of the scrubber and is withdrawn through line 13 at condenser pressure.

The scrubbing liquid, together with water and oil withdrawn from the S0 vapors, leaves the bottom of the scrubber or contact device 7 by line 8 and joins the raflinate or extract entering heater 9 by line 3. In this way none of the water and light oil contained in the railinate and extract is permitted to escape from the corresponding first stages of the respective rafiinate and extract evaporation systems.

Referring again to Fig. 1, the raflinate or extract, as the case may he, leaves condenserpressure evaporator 10 by line 14, freed of a certain amount of S0 but still containing all of its original water and light oils.

Line 14 leads to atmos )heric-pressure evaporator 15. The S0 vapors leaving from this stage are very rich in water and light oil vapors, since none were withdrawn in the previous stage, and are withdrawn from evaporator 15 by line 16 which leads into gas cooler 17 and light oil separator 18, which serve as a. partial condenser to remove the oil vapor constituents. The condensed oil is withdrawn from separator 18 by line 39. The remaining vapors pass into dryer 19, where the water constituent is removed, and leave by line 20 as a substantially pure S0 gas.

The unevaporated raflinate or extract flows from evaporator 15 by line 21 to vacuum evaporator 22, where the remaining S0 content is evaporated off, together with a certain amount of water and light oil. These vapors leave by line 23 and are raised by gas pump 24 to the pressure of the vapors in line 16, to which they are then joined by means of line 25. It will thus be seen that oil separation means 17, 18, and dryer 19, serve to purify the vapors from both atmospheric pressure evaporator 15 and vacuum evaporator 22. Line 26 serves for withdrawing the railinate or extract from last stage (vacuum) evaporator 22.

It is evident that the raflinate or extract from the mixer, entering the evaporation system by line 1, leaves the system by line 26 freed of its S0 content. And that the extracted SO leaves the system by lines 13 and 20 as a substantially pure S0 gas fit for reuse (aflter liquefaction) in the main treatment cyc c.

Fig. 3 shows a second form of the invention wherein first stage condenser-pressure evaporator 10 and contact device 7 (shown in Figs. 1 and 2) are replaced by a combined vertical evaporator and contact device 29. IThe remainder of the system is as shown in As before, the raflinate or extract from the mixer enters by line 1 and is divided into two parts. A portion flows directly by line 3 controlled by valve 4) through heater 9 into t e lower portion of vertical evaporator-contactor 29 where a certain amount of the S0 content is freed and rises as a vapor, together with a quantity of water and light oil vapors. The diverted portion of the raflinate or extract from line 1 flows by line 5 (controlled by valve 6) to the upper middle portion of evaporator-contactor 29, where it is directed downwardly as a spray by sprinkler 37, and falls countercurrently to the ascending S0 vapors which are thereby scrubbed substantiall free of water and'oil vapor content. Ba e plates 30 are disposed below s rinkler 37 an increase the contacting e ciency. Filling material 31 is placed above the sprinkler and serves to retain any rafiinate or extract parts which may have been pulled along with the SO, vapors. Line 32 withdraws substantiall pure S0, at condenser-pressure from c top of t e evaporator-contactor. The uneva rated raflinate or extract leaves by line 1 for further treatement as shown in Fig. 1.

It will be seen that in this embodiment the contacting or scrubbing liquid, together with the water and oil extracted from the SO, vapors, asses directly down into the evaporating hquid, and it is not led through the heater 9 as in the first embodiment.

Fig. 4 shows a third form of the invention wherein the contact means are installed in dome 11 of the con sneer-pressure evaporator 10 shown in Figs. 1 and 2. As in the first form, also shown in Fi 1 and 2, the raiiinate or extract entering t e evaporating system b line 1 is divided into two portions, one of w heater 9 into evaporator 10 in which part of the SO, content is freed and rises as a vapor, together with a quantity of water and hght oil vapors, into dome 11. The diverted portion of the raflinate or extract flows through line 5 into the upper part of dome 11 and is directed downwardly by sprinkler 35, scending countercurrent y to the ascending vapors and scrubbiliifinhem free of water .an oil constituents. F' below the sprinkler so as to increase t e efiicienc' of the contacting or scrubbing. Substantially pure SO, gas at condenser-pressure leaves the top of .dome 11 by line 33. As in the second form of the invention, shown in Fig 3, the scrubbing liquid, to ether with water and oil withdrawn from t e SO, vapors, descends directly into the evaporating liquid; Line 14 serves to withdraw the unevaporated rafiinate or extract for further treatment as shown in Fig. 1.

Fig. 5 shows a com lete set u for the separation of water free 0, from oth the railinate and extract. Two evaporation systems, each according to the form shown in Fig. 1, are employed, one for the raflinate and one for the extract.

The evaporation system shown in the lower half of Fig. 5 is identical with the evaporation system shown in Fig. 1 and the same reference'characters are used to designate the corresponding parts. The evaporation s stem shown in the upper half of Fig. 5 is a 0 identical and the corresponding parts are designated by the same reference characters primed.

Assuming the extract from the mixer to enter the evapor ion system comprising evaporators 10, 15 an 22 and contact device 'ch flows directly by line 3 through g material 36 is laced or scrubber 7, water-free SO, as at condenser ressure will passfrom scrub er 7 by line 18. n the same way, water-free SO, gas at condenser mpressure will leave by line 13 from the ra nate evaporation system comprising evaporators 10', 15' and22' and scrubber 7 into which raiiinate from the mixer enters b line 1. The S0,. as in lines 13 and 13' 1s combined in line and is ready for direct condensation at cooling water temperatures and subsequent reuse in the refining system.

The extract and rafiinate, freed of a certain amount of SO, but containing all of the original water and light oils, flows from evaporators 10 and 10, respectively, and passes to atmospheric pressure evaporators 15 and 15' by way of lines 14 and 1 The SO vapors leavin from these evaporators by lines 16 .and 16 are rich in water and light oil vapors and flow into line 41.

The extract and raflinate flow from evaporators' 15 and 15, by way of lines 21 and 21,

into vacuum evaporators 22 and 22', respec tively, where the remaining SO, content is evaporated oil, together with a certain amount of water and light oils. These vapors leave by lines 23 and 23' and are brought together in line 42 and are then compressed up to atmospheric pressure by pump 24, from which they flow through line 25 into line 41, joining the SO, vapors from the atmo heric ressure evaporators.

T e com ined SO, vapors in line 41 are then led into as cooler 17 and light oil separator 18, whic serve as a partial condenser to remove the oil va or constituents. The condensed oil is wit drawn from separator 18 by line 39. The remaining vapors pass into dryer 19, where the water constituent is removed, and leave by line 20 as a substantially pure SO, gas.

The purified extract leaves its evaporation by line 26 and the purified raflinate leaves its evaporation system by line-26'.

It will be obvious that the contact devices previously described, and illustrated in Figs. 3 and 4, may be substituted for the form shown in Figs. 1 and 2, embodied in the system just described and illustrated inFi 5. The advantage of the system shown in %i 5 is that only one gas pump 24, gas cooler 1 light oil separator 18 and drying device 19, are .used for the SO, vapors from both the extract and raflinate evaporation systems.

In some installations it may be advanta ous to equip" all evaporators with contact evices such as above described. With the lower pressure evaporators it would be of advantage in this case to use a part of the finished product (extract or rafiinate) as sprinkling liquid. Or it may be found necessary to use contact devices only for the extract evaporators as the amount of SO, carried OR by the rafiinate is not relatively great.

The invention obviously is not restricted to the particular embodiments thereof herein illustrated and described.

Havi iw lisclosed three illustrative embodiments 0 the invention, what is claimed and desired to be secured by Letters Patent is as follows:

1. In the rocess for continuous treatment of hydrocarbons with liquid-S0 or the like, the method of recovering the S0 contained in hydrocarbon mixtures containing moisture, comprising the steps of subjecting the mixture to mu ti-stage evaporation for removal of the S0 therefrom, the first stage being at condenser pressure and succeeding stages at not greater than atmospheric pressure, returning the water and hydrocarbons contained in the S0 vapors evolved from the first stage to the evaporation system, and removing the Water and hydrocarbons contained in the S0 vapors evolved from said succeeding stages but without returning the removed water to the evaporation system, whereby the S0; is recovered as a substantially pure gas for condensation and reuse in the treatment cycle. I

2. In the process for continuous treatment of hydrocarbons with liquid-S0 or the like, the steps comprising subjecting the moisture containing rafiinate and extract from the mixer to separate muti-stage evaporation for removal of the S0 therefrom, the respective first stages being at condenser-pressure and the succeeding stages at not greater than atmos heric pressure, removin the water and ydrocarbons from the O vapors evolved from the first stages by scrubbing with rafiinate and extractfrom the mixer, respectively, introducing the liquid products of said scrubbing into the evaporation syste'ms, and removing the water and hydrocarbons contained in the S0 vapors evolved from said succeeding stages but without returning the removed water to the evaporation system, whereby the S0, is recovered as a substantially pure gas for condensation and reuse in the treatment cycle.

3. An improvement in the system for continuous treatment of liquid h drocarbons with liquid-S0 comprising su jecting the raliinate and extract from the mixer to separate multi-stage evaporation for removal of the S0 therefrom, the respective first stages being at condenser pressure and the succeeding stages at not greater than atmospheric pressure, removing the water and hydrocarbons from the S0 vapors evolved from the first stages by contacting said vapors with cool rafiinate and extract from the mixer, respectively, introducing the liquid products of said contacting into the respective evaporation systems, collecting the SO, vapors evolved from the succeeding stages, uniting at atmospheric pressure said vapors from the succeeding stage, and removing the hydrocarbons and water therefrom but without returning the removed water to the evaporation system, whereby the S0 is recovered as a substantially pure gas for condensation and reuse in the treatment cycle.

4. An improvement in the system for continuous treatment of. liquid h drocarbons with liquid-S0 comprising su jecting the moisture containing raflinate and extract from the mixer to separate multi-stage evaporation for removal of the SO, therefrom, the respective first stages being at condenser pressure and the succeeding stages at not reater than atmospheric pressure, contactlng the S0 vapors evolved from the respective first stages with a portion of the rafiinate and extract on route from the mixer to the evaporation systems so as to secure the return of the hydrocarbons and water contained in said vapors, collecting the S0 vapors evolved from the succeeding stages, uniting at atmospheric pressure said vapors from the succeeding stages and condensing out the hydrocarbons present, followed by drying the S0 but wlthout returning the removed water to the evaporation system to secure substantially pure S0 gas for condensation and reuse in the treatment cycle.

5. In combination with the process for continuous treatment of liquid h drocarbons with liquid-S0,, the method 0 separating and purifying the S0 contained in the raflis nate and extract so as to permit of repeated use in the treatment cycle, comprising subectlng the raflinate and extract from the mixer to separate multi-stage evaporation, the respective first stages being at condenser pressure, the second at atmospheric ressure and the final under vacuum, scrub ing the SO, vapors evolved from the respective first stages with a portion of the rafiinate and extract en route from the mixer to the evaporation systems so as to secure the return of the hydrocarbons and water contained in said vapors, collecting and compressing to atmospheric pressure the S0 vapors evolved from the final stages and unitin the same with the S0 vapors collected rom the second stages, respectively, condensing out the h drocarbons therein, and lastly drying e SO gas from said second and final stages but without returning the removed water to the evaporation system.

6. The method specified in claim 3, wherein the SO, vapors from the condenser-pressure first stage evaporators are conducted to separate towers and therein contacted with countercurrent sprays of cool raflinate and extract, respectively, from the mixer, the contacting liquids, together with included bydrocarbons and water extracted from the S0 vapors, being then led to the inputs of the respective first sta e evaporators.

7 The method specified in claim 3, wherein the first stages of evaporation are per formed in vertical chambers into the upper parts of which are introduced respective descending sprays of cool rafiinate and extract from the mixer for contacting with the ascending SO, vapors and rendering them free of hydrocarbons and water.-

8. The method specified in claim 3, wherein descending 'sprays of cool railinate and extract from the mixer are introduced into the respective domes of horizontal first stage evaporators for contacting the SO, vapors ascending to S0, outlets in the tops of said domes, whereby said SO vapors are rendered free of hydrocarbons and water.

9. The method s cified in claim 5, wherein the raflinate an extract to beevaporated in the respective first stages are first heated and then allowed to evaporate in respective horizontal chambers, the SO, vapors therefrom being conducted to towers and scrubbed by descending sprays of a portion of the cool raflinate and extract from the mixer, which materials, together with included h drocarbone and water, are then joined wit the remainder of the raflinate and extract from the mixer and introduced, after heating, into the respective first stage evaporators.

10. The method specified in claim 5, wherein the rafiinate and extract to be evaporated in the respective first stages are first heated and then allowed to evaporate in respective vertical chambers into the upper parts of which are introduced descending sprays of a portion of the cool rafiinate and extract from the mixer for scrubbing the'ascending S0 vapors and returning the hydrocarbons and water contained therein to the rafiinate and extract in the evaporators.

11. The method specified in claim 5, wherein the rafiinate and extract to be evaporated in the respective first stages are first heated and then allowed to evaporate in res ctive horizontal chambers provided with S 2 outlet domes into which are introduced respective descending sprays of a portion of the cool rafiinate and extract from the mixer for scrubbing the SO: vapors ascending through the dome and returning the hydrocarbons and water contained therein to the raifinate and extract in the evaporators.

12. An improvement in the system for con tinuous treatment of li uid h drocarbons with liquid-S0 comprising su jecting the moisture containing rafiinate from the mixer to multi-stage evaporation for removal of the S0 therefrom, the first stages being at condenser pressure and the succeeding stages at not greater than atmospheric pressure, removing the water and hydrocarbons from the S0 vapor evolved from the first sta e by contacting said vapors with cool ma nate from the mixer, introducing the liquid products of said contacting into the evaporatin system, collecting the S0 vapors evolv from the succeeding stages, uniting at atmospheric pressure said vapors from the succeeding stages, and removing hydrocarbons and water therefrom but without returning the removed water to the evaporation system, whereby the S0, is recovered as a substantially pure gas for condensation and reuse in the treatment cycle.

13. An improvement in the system for continuous treatment of liquid hgdrocarbons with liquid-S0,, comprisingsu jecting the moisture containing extract from the mixer to multi-stage evaporation for removal of the S0 therefrom, the first stage being at condenser pressure and the succeeding stages at not greater than atmospheric pressure, removing the water and hydrocarbons from the SO, vapors evolved from the first stage by contacting said vapors with cool extract from the mixer, introducing the liquid products of said contacting into the evaporating system, collecting the S0 vapors evolved from the succeeding stages, uniting at atmospheric pressure said vapors from the succeedin stagesfand removing the hydrocarbons an Water therefrom but without returning the removed 'water to the evaporation s stem, whereby the S0 is recovered as a su stantially pure gas for condensation and reuse in the treatment cycle.

14. In combination with the process for continuous treatment of liquid h drocarbons with liquid-S0 the method 0 separating and purifying the S0 contained in the rafiinate so as to permit of repeated use in the treatment cycle, comprising subjecting the moisture containing raffinate from the mixer to multi-stage evaporation, the first stage being at condenser pressure, the second at atmospheric pressure and the final under vacuum, scrubbing the SO, vapors evolved from the first stage with a portion of the rafiinate en route from the mixer to the evaporation system so as to secure the return of the hydrocarbons and water contained in said vapors, collecting and compressing to atmospheric pressure the S0 vapors evolved from the final stage and uniting the same with the S0 vapors collected from the second stage, condensing out the hydrocarbons,

therein, and lastl drying the S0 gas from said second and final stages but without returning the removed water to the evaporation system.

15. In combination with the process for continuous treatment of liquid hydrocarbons with liquid-S0,, the method of separating and purifying the S0 contained in the extract so as to permit of repeated use in the treatment cycle, comprising subjecting the moisture containing extract from the mixer to multi-stage evaporation, the first stage being at condenser pressure, the second at atmospheric pressure and the final under vacuum, scrubbing the S0 vapors evolved from the first stage with a portion of the extract en route from the mixer to the evaporation systo this sgecifi' ation. name IUSEPPE CATTANEO.

csnrmcmaor connection.

Patent No. l, 913, 658.

June 13, 1933.

GIUSEPIPE CATTANEO.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 35, for "compresed" read "compressed"; and line 67, after "with" insert "the"; page 4, line 30, claim 2, for "nluti-stage" read "multi-stage"; lines 50 and 99, claims 3 and 5, before "raffinate" insert "moisture containing"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of August. A. D. 1933.

(Seal) II. J. llaote.

Acting Comissioner of Patents.

to this sgecifi' ation. name IUSEPPE CATTANEO.

csnrmcmaor connection.

Patent No. l, 913, 658.

June 13, 1933.

GIUSEPIPE CATTANEO.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 35, for "compresed" read "compressed"; and line 67, after "with" insert "the"; page 4, line 30, claim 2, for "nluti-stage" read "multi-stage"; lines 50 and 99, claims 3 and 5, before "raffinate" insert "moisture containing"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of August. A. D. 1933.

(Seal) II. J. llaote.

Acting Comissioner of Patents. 

